Epinephrine is a catecholamine that stimulates the α- and β-adrenergic receptors of the sympathetic nervous system. Epinephrine binds to these adrenergic receptors leading to relief of many life-threatening symptoms of anaphylaxis (e.g., relaxation of the smooth muscle in the bronchi of the lungs thereby opening up constricted airways, constriction of the blood vessels leading to decreased swelling of the tongue and throat and increasing blood pressure, and increased heart rate thereby preventing or reversing cardiovascular collapse).